Where does “rěk-” come from?

rěk- (Proto-Slavic) comes from Proto-Slavic -ь, from Proto-Indo-European -is — Forms nouns from verbs.

Ancestry of “rěk-”, step by step

StepLanguageWordMeaning
1Proto-Slavic-ьForms nouns; From adjectives; From participles
2Proto-Indo-European-isForms nouns from verbs

Words derived from “rěk-”

Every word from Proto-Indo-European -is →Every word from Proto-Slavic -ь →